Plier-type, toggle actuated wrench



May 15, 1951 J, BLA|R 2,553,400

PLIER-TYPE, TOGGLE ACTUATED WRENCH Filed March 15, 1946 2 Sheets-Sheet lINVENTOR.

May 15, 1951 J. A. BLAIR PLIER-TYPE, TOGGLE ACTUATED WRENCH 2Sheets-Sheet 2 Filed March 13, 1946 INVENTOR.

fif 5142/.

Patented May 15, 1951 "BIKER-TYPE, TOGGLE ACTUAT-ED WRENCH ,l'ohn A.Blair, Pleasant Ridge, Mich., assignor to lKa'thryn K.'Blair, PleasantRidge, Mich.

App'lication'March .13, 1946, Serial'No. 654,065

12 .Claims.

The :present invention melates to an automat- :ically adjustable awrench:having parallel jaws and is a .continuation-in-gpartof .my copendingapplication on Wrench, :Serial .No. 640,047, filed JanuaryS, 1946,. nowabandoned.

The jaws of an wrench used-on nuts and the like must present fiatparallel .faces and must closely fit thenut -,to.-;avoid;a destructiveconcentration of load at the corners of the nut when it :is turned.InSthat-connection, the load applied at each .of two corners =ofahexagonal .nut for a five-eighths inch bolt by a fifty pound pull at theend of a ten inch wrench riS approximaely twelve hundred pounds. Higherloads are frequently exerted .in :actual practice. Such loads .not :bemade to .fit the corresponding nut with suflicient accuracy to avoidobjectionable concentration of the twisting load at two corner of the:nut for the reasonthat -'a-close fit would make their application tothe nut difficult. To make -;application practical, substantialclearance is specified in the United Statesfitandard for open end.wrenches (.006" for .a nut). This necessary clearance is so high thatsocket wrenches which distribute the lead .over all corners :of the nutare preferred to openend wrenches where it is possible to use .them.With either type 'a separate wrench is required for each size nut, whichis 1 exceedingl inconvenient.

Many attempts have been made towdevisea satisfactory adjustable wrenchin order to avoid .the necessity of carrying and selecting the proper.one of a multiplicity of wrenches in assembling and repairingmachinery. The most widely used adjustable wrenches have a sliding jja-wwhichis adjusted relative to the other jaw by a .screw. FI-hese may beopened up for easy application and then tightened on the nut .before thenut is turned. However, distortions and unavoidable play between therelatively :sliding parts permit the gja-wsto open-slightly under loadand even a deflection of a few 'thousandth's of an inch is ob-;jectionable. :In addition, the necessary :manipw :lations of theadjusting screw are troublesome, particularly when the wrench must beused in places which are not within the range :of vision of themechanic. .a :result of these defec 2 fixed wrenches :of the :socket oropen :end type are used very extensively in preference to ad-.justablewrenches.

Many other forms of adjustable wrenches have been devised. Some havebeen automaticall adjustable but are usable onl as pipe wrenches becausethey do not maintain the jaws in ;parallelism.

Parallel jaw .pliers have (been proposed but these generally rely:onhand-gripping pressure to resist the forces exerted against the jaws. Ifsufficient force multiplying mechanism is provided for this purpose, as,for example, by a toggle mechanism, the movement of the jaws.is'insufficient to permit use on :more than one size of nu" un ess anauxiliary adjustment of some kind is also provided. Prior ;paral:el jawtoggle pliers have, moreover, employed parallel linkages which aresubject to :bending stresses and excessive distortion.

Many oftheproposed automatically adjustable wrenches have employed someform of ratchet mechanism 'for locking the Jews in any oneof a plurality:of positions. Most of these have been defective :because no provisionwas made for fit- .tingtnut :s'izes intermediate the possible positionsof adjustment of the ratchet. Inaddition, all such wrenches .herefiofore:propo ed have been -peculiarly subject to spreading, distortion andmisalignment or non-parallelism of the jaws under load. Moreoven'noprior ratchet type constructions have embodied a ratchet mechanismcapable of withstanding the high .s'resses encountered in the normalusesofaa-wrenoh. .In that connection, it should be noted that in orderto carry heavy loads, engagement Of a substantial tooth .tareaisrequired. .No -:one ratchet tooth can carry sufiicient load unless .it:is :so large that the increments :of adjustment rof the wrench areexcessive. All prior attempts to distribute the load over .a plurali yof 'teeth have :involved iIXIBChfinismswhich did not insure engagementto the full tooth depth and -.'distribution of the load on all teeth."Consequently, there is serious danger of stripping or mangling theteeth.

Accordingly, it .is one :object of the presentinventionto provideawrench which'will automatically grip :a'range of different sizenutswithless angularity between the laws and the .nut faces than'is encountered:in standard fixed wrenches.

Another object of the present invention is to provide an adjustableparallel jaw wrench which "may by a single convenient manipulation beclosed .on any .size nut within a relatively wide :range :oI sizes andthereafter :bring into action anism in which a load carrying engagementto.

the full depth of the teeth and over a substantial tooth area ispositively insured and in which the teeth are of a form which providesmaximum strength.

Another object of the present imvention is to provide a wrench having aratchet adjusting mechanism in combination with means for automaticallycompensating for the inherent incremental characteristic of the ratchetmechanism so that the wrench will close on and clamp any 'size nut;

Another object of the invention is to provide a wrench in the form of apair of toggle acting pliers in which a normal squeezing of the handlestoward each other automatically closes the jaws 'on any size nut andapplies a final toggle clamping action. 7

Another object of the invention is to provide a toggleplier wrench ofthe type mentioned in which the jaws are maintained in substantialparallelism Another object of the invention is to provide a toggle plierwrench in which'the final position of the free ends of the handlesremains approximately the same regardless of variations in the size ofthe nut to which it is applied.

Another object of the invention is to provide a wrench of the typementioned which, by a simple manipulation, may either have self-lockingor automatic releasing characteristics.

Other objects, which include the provision of a wrench of the typementioned which is simple and rugged in construction, will becomeapparent from the following specification, the accompanying drawings andthe appended claims.

In the drawings:

7 Figure 1 is a side elevation'of the preferred form of the invention,with parts broken away and showing the wrench in fully open position;

I Figure 2 is a side elevation showing the wrench in its fully closedposition;

Figure 3 is a transverse section taken on the line 3-3 of Figure 1; I

Figure 4 is a transverse section taken on the linedi of Figure 1;

Figure 5 is a transverse section taken on the line 5 "5 of Figure 1;

Figure 6 is a transverse section taken on the line 66 of Figure 1;

Figure 7 is a fragmentary enlarged longitudinal section taken on theline 1-"! of Figure 6; Figure 8' is a greatly enlarged fragmentary,longitudinal section similar to Figure 7 showing the manner in which theratchet teeth approach clamping the jaws on a nut after they haveengaged the nut and after the ratchet mechanism has engaged. Thisclamping mechanism is capable of giving the jaws a small additionalclosing movement sufiicient to cover the gap between the increments ofadjustment of the ratchet mechanism, and has sufficient forcemultiplying capacity to apply the required jaw gripping force inresponse to ordinary hand pressure. In order to accomplish that result,the ratchet teeth are made quite small and the load is distributed overa plurality of teeth. Since this provides small increments of adjustmentof the ratchet, the clamping mechanism need not transmit any appreciablemovement and hence may have the requisite force multiplication. Thewrench is so constructed that by a single hand movement in onedirection, the'normally open jaws are closed on a, nut and thereafterthe clamping force applied. The ratchet mechanism becomes effectiveautomatically in response to engagement of the nut by the jaws, and theclamping mechanism becomes effective after the ratchet mechanismengages.

In the preferred form of the invention shown in the drawings, the wrenchresembles a pair of pliers and the clamping mechanism is a tog glelinkage. Thus, as best shown in Figures 1 and 2, the Wrench comprises apair of handles 1 and 2 which are positioned relative to each other inthe manner of the handles of a pair of pliers. The handle 2 ispreferably formed as a unitary forging with an integrally fixed jaw 3.The handle forging has a centrally located web portion 4 which extendsthe full length of the handle and a Wider flange portion 5, which alsoextends the full length of the handle 2 and termi nates in a U-shapedsection 6, shown best in Figure 3. The web portion 4 is providedintermediate its ends with a generally triangular opening I, which is made ofsubstantial size in order to lighten the tool and which also serves anadditional purpose hereinafter mentioned. At the rear of opening 1, theweb is further reduced in thickness at 8. The web is also provided withan opening 9 located forwardly of the opening 1 and separated from thelatter by an intermediate web portion H]. The forward wall of theopening 9 is formed with a series of ratchet teeth ll and the opening isgenerally in the form of an elongated slot extending approximatelyperpendicular to the face of jaw 3.

Positioned within the opening 9 is a ratchet pawl I2 having a pluralityof teeth l3 adapted to mesh with the previously mentioned teeth II. Thepawl I2 is press fitted or otherwise fixedly secured to a pin l4 havinga flattened portion l5 adapted to prevent rotation of the pawl relativeto the pin.

lines at It in Figure 7, adapted to co-operate with the fiat surface [5on the pin M to limit rotation of the pin within the openings in theside plates. The space between the fiat surfaces [8 of the openings inthe side plates I! and flat IS on the pin I4 is sufficient only topermit the minute rocking movement of the pawl I2 necessary to maintainfull contact between the teeth H and I3 during the limited pivotalmovement of the jaw l6 relative to the axis .of pin 14 inch dent to.operation of the toggle mechanism hereina-fter described in greaterdetail.

The jaw [6 may be made up in any desired manner but, as illustrated,comprises an integral element of generally channel shape with the sideplates connected by a web, the inner surface of which i curved in themanner indicated in dotted lines in Figure 1, and merges with the jawface 19.

The rear end of the web of jaw 16 projects beyond the rear edges of theside plates .11, as best shown in dotted lines at 2.0 in Figure 1, andis provided with a transverse opening to receive a pivot pin 2|. Thehandle :1 is *formed as a stamping having a generally U-shaped crosssection providing relatively deep side wall .portions 22 which embracethe projecting portion 20 of the jaw l6 and also a substantial portionof the web 4 of the handle 2. The side plates 22 are provided withsuitable openings to receive pivot pin 21. The handle comprises one linkof a toggle linkage including an additional link 23, which is pivotedbetween the side wall members 22 .of the handle I by means :of a pin 24at one end, and is pivoted within the U-shaped terminus .6 vof thehandle -2 at the other end by means of a pivot pin .25. Asa result ofthis construction, separation of the handles l and ,2 tends to break theggle linkage and thereby swing the jaw 1.6 about the pin I 4 in aclockwise direction, and squeezing of the handles together effects areverse rotation of the jaw I .6 about the pivot pin 1-4.

:Suitable means are provided to break the toggle linkage and thusmaintain the handles and .2 in a separated position. In the preferredform of the invention illustrated, this means comprises a link 26, whichis pivoted by means .of .a pin 2.1 between the .side walls 22 of thehandle I and .a helical spring 28, one end of which is secured in anopening 29 in the extremity .of the handle 1 and the other in an opening3!! in the link 26. Thearrangement is such that the spring .28 normallytends to swing the link 26 in a counterclockwise direction about the pin2,1,,as viewedin Figure 1, thus tending to .break the toggle linkage.The link is provided with a pair of grooves 13.1 .in order to provideclearance between the link ,and the side walls 22 for the end of thespring .23.

The toggle breaking movement effected by the spring .28 and link 26 islimited .to a relatively small angle by means of an abutment surface 32formed .on the left-hand extremityof the link 23 and adapted to abut theunderside of the top wall of the handle I when .the parts are in theirfully opened position,,i1lustrated in Figure 1. ,In that position, aflattened end portion .33 on the link 25 bears against the top surfaceof the ,link 23. This flattenedsurface is so arranged that the linkextends at a small angle from a normal to the top surface of the link23. This-angle slightly exceeds the angle of repose for the materials ofthe link 26 and lever 23, with the result that upon application of aclosing force to the handle .I, the end of the link 26 will tend toslide to the left, as viewed in Figure 1, along the topsurface of lever23. The spring 28 is a relatively light spring which resists thismovement. The arrangement is such that an appreciable closing force mustbe applied to the handles before the link v26 will slip to the left, butas soon as such movement is started, .the link .25 will swing to theposition shown in Figure 2 and the resistance to closure of the handlesinduced by the spring .28 will .be reduced toanegligible value byreasonof.

tp le linkage.

the tact that the line of force exerted by the spring approaches closelyto the axisof pin 21. In the fully straightened toggle positionillustrated in Figure 2, a nose 3.4 on the link .26 engages theunderside of the top wall of the handle I to limit the togglestraightening action.

If, as is preferred in the operation of a wrench, it is-desired to havethe jaws release automatically when the pressure on the handles isrelieved, the nose 34 is so constructed that it stops the togglestraightening movement just short of the fully straightened position.

The wrench also incorporates means to swing the upper jaw in acounterclockwise direction about pin 2| to a limited extent sufficientto effect disengagement of the teeth H and 13. In addition, means areprovided to urge the upper jaw l 6 upwardly, as viewed in Figure ,1,inorder to main! tain the jaws in a normally open position.

In the preferred form of the invention illustrated, both of thesefunctions are performed by a single mechanism comprising a lever 35.anda helical spring 35, best shown in Figure 1. One end of the lever 35is pivoted on a pin 3 carried by :a pair of cars 38 formed on the flange.5 of the handle portion 2, as best shown in Figures 1 and .5. Theopposite-extremity of the lever .35 is twistedat 39 throughan angle of90 with respect to the plane of the lever and is provided with a pair ofoppositely projecting lugs 41!) which project into slots AI formed inthe side plates J1 of the upper jaw I6, in the manner best shown in Figure .2, The slots Al extend at an angle of approximately with resp ct tothe plane ef the jaw iaces and, consequently, the force exerted upon thetop walls of the slots 41 by the lugs 40 is in a direction to not onlyseparate the laws but to cause a rotation of the upper jaw in .acounterclockwise direction about the pin 2| when the lever 35 is urgedin a clockwise direction about its pivotpin31. :Qne end of the spring 36isfixed in an opening 42 in the thinner web section -8 and the'oppositeend in an opening 43 formed in the lever .35 adjacent its outerextremity, thus tending to swing the lever 35 in a direction to separatethe jaws and at the same time to separate theteeth H and 13.

As a result of the above described mechanism, the wrenchnormallyoccupies the fully open position illustrated in Figure 1, withthe toggle linkage broken to the full extent permitted by the limitingabutment 32. When it is desired to clamp the wrenchon a nut, the jawsare placed over the nut in the usual manner and the handles l and .2squeezed together :byasingle hand pressure. The arrangement of thelevers 26 and 35 and the springs 28 and is such that a pres.- sureapplied by the hand to the handles suflicient to overcome the forceexerted by lever 35 will close the jaws of the wrench on the nut withoutovercoming the tendency of the lever 26 and spring 28 to maintain thetoggle linkage in its fully broken position. As a result, the togglelinkage, comprising the link '23, andthe hand-1e pivot bodily about thepin 25 to close the jaws on a nut.

During such movement, the force exerted by the lugs 46 of lever 35-ontheupper jaw I36 holds the pawl l2 out of contact with the teeth I l andthe pawl rides along the smooth back wall Jlllrof the opening 9 withoutany straightening of the .As soon as the jaw L6 engages thenut, .itsbodily movementtcward the jaw 3 will be'arrested and continued pressureon the handles "will tend to move the pivot pin 2| downwardly while thejaw fulcrums to a limited extent about its point of contact with thenut. This rocks the jaw in a clockwise direction about pin 2|simultaneously with the downward movement of the pin 2|, thereby movingthe pawl I2 downward and to the left, as viewed in Figures 1 and 2,until the teeth I3 engage the teeth II. After the teeth have engaged,pin 2I can no longer move downwardly and, consequently, application offurther presure to the handles will cause link 25 to slip to the leftalong the top surface of lever 23 and the toggle links will bestraightened. This straightening action will rock jaw IS in acounterclockwise direction about pin I4 to a limited extent, andthusapply a strong clamping action to the nut located between the jaws.

It is desirable to limit the force required to effect a closure of thejaws on a nut and, consequently, the lever 35 and spring 36 are soconstructed that they exert the minimum jaw opening force necessary.Moreover, the arrangement of the spring 36 and the lever 35 is such thatas the spring is stretched incident to closure of the jaws, the leverarm through which the spring force acts upon lever 35 decreases, withthe result that the torque applied to the lever 35 is substantiallyconstant in all positions of the lever. Lever 26 and spring 28 are thenso constructed that they will maintain the toggle linkage broken whensubject to a force sufficient to close the jaws, but will permit togglestraightening action on a slight increase in that pressure.

The construction, location and arrangement of the ratchet holdingmechanism is such as to provide maximum holding strength and maintenanceof the jaws of the wrench so nearly parallel at all times that theminute departures from true parallelism, which result from the limitedswinging movements of the jaw I6, are more than compensated for by thetoggle clamping action of the jaw on a nut. These results flow from anumber of specific features of the wrench construction. Thus, in thepreferred construction the teeth II and I3 are made as small as it ispossible to manufacture them practically and still maintain a highdegree of accuracy in tooth form and spacing. As a specific example, fora, wrench of high quality and accuracy, the tooth spacing may be made assmall as twenty-five one thousandths of an inch. As a result of thesmall size of the teeth, it is necessary to distribute the very highloads which they must carry over a relatively large number of teeth, asindicated on an enlarged scale in Figure '7. Moreover, it is necessarythat all of the teeth on the pawl I2 make full depth engagement with theteeth II in order .to properly and accurately distribute the load.

through the pawl I2 to the teeth I I passes through teeth of pawl I2intermediate the ends of the toothed surface of the pawl, as indicatedby the dotted line arow 45 in Figure '7. The direction of this force issuch that the pawl will swing automatically about the axis of pin I 4until all of the teeth I3 on the pawl I2 seat squarely against the teethII.

It will be noted that the direction of the resultant force applied tothe ratchet teeth, as indicated by the line 45, is an angle ofapproximately 45 to the faces of the jaws. This results from therelative positions of the axes of pins I4 and 2| relative to the face ofjaw I6. Thus,

7 tial contact exactly with the points of teeth II.

as shown in Figure 2, when the wrench is clamped upon an object, thetoggle linkage will exert a force indicated by the dotted line arrow 46on the jaw I6, while the object which is clamped will exert a verticallyacting force on the face of the jaw I6. The location of this latterforce may b at any point along the length of the jaw face but, under theworst condition that may arise, will be concentrated at the innermostportion of the face, as indicated by dotted arrow 41. Since the distancefrom the innermost portion of the face of jaw I5 to the line connectingthe axes of pins I4 and 2I is approximately equal to the distancebetweenthe axes of pins I4 and 2|, the resultant of the forces indicatedby arrows 46 and 41 extends at an angle of 45 to the jaw faces, asindicated by dotted line arrow 45. If the load applied to the jaw I6 islocated further out on the jaw, the resultant of forces 46 and 4! willextend at an angle slightly less than 45 with respect to the jaw facesbut will not depart from the 45 angle by an amount sufiicient to causecocking'of the pawl I2.

By so locating the points of application of the forces on the upper jawthat the resultant force on the pivot pin I4 extends at an angle ofapproximately 45" to the faces of the jaws, it is possible to constructthe teeth II with side faces which make an angle of 45 with respect tothe jaw faces and which, consequently, make an angle of 90 with eachother, as shown in Figure 8. That form of. tooth may be used without,danger of slippage between the pawl and the teeth I I by reason of thefact that the direction of the force 45 is approximately normal to theunder sides of the teeth 5| under the worst possible conditions. A majoradvantage of teeth so formed is that they provide the maximumstrengthbecause the loads applied to them are pure compression loads,thus eliminating all bending and shearing stresses on the teeth.

In order to utilize the full load carrying capacity of teeth I I and I3,it is not only necessary to provide the automatic self-aligning pawlconstruction previously .described, but it is also necessary to insurethat teeth I3 engage to the full depth of the teeth II at all times.Such full depth engagement is positively insured in the i1.- lustratedembodiment of the invention by reason of the fact that the path ofmovement of the points of the teeth I3, as they approach the teeth II,is in such a direction that initial contact between the teeth II and I3will occur at the upper sides of the teeth I I, while in the final position the load is taken by the lower sides of the teeth i I. As aresult, straightening of the toggle linkage causes the teeth I3 to slideup the upper surfaces of teeth II into full depth engagement. Initialengagement at the upper sides of teeth II always occurs because pins I4and 2i are moving downwardly during the limited rocking move- 'ment ofthe jaw I6, which occurs after it engages an object located between thejaws. and before the toggle linkage is straightened. Thus the points ofthe teeth I3 have a resultant movement parallel to the path indicated bydotted line 7 48 in Figure 9.

The location of the line 48 extending between any pair of engaging teethwill depend upon the thickness of the object engaged by the jaws. Forcertain thicknesses of objects, it is theoretically possible to have thepoints of teeth I3 make ini- That condition, which is illustrated inFigure 8,

is the worst condition that can arise because in such case the finalengagement may occur onehalf a tooth space above or below the point ofinitial contact for a negligible variation in the size of the objectclamped. This variation in position of the dog is compensated for by theswinging of jaw It about pin I4 incident to operation of the togglelinkage, However, to obtain maximum mechanical advantage and minimum.departure from parallelism, this swinging movement should be as smallas possible and, therefore, the teeth should be as small as practicable.Even where initial engagement of the teeth occurs point to point, finalengagement will be to full tooth depth because if the points of theteeth catch during movement of teeth 5 3 along the line 48, thesubsequent change in the direction of the forces caused by straighteningthe toggle links will cause the points of teeth l3 to slide inwardly onthe upper sides of teeth I l.

Another factor affecting the degree to which the jaws remain parallel inclamping position and the amount of movement which the toggle linkagemust transmit to pin 2| is the width of the opening 9 as compared withthe size or" the pawl l2. The clearance between the pawl and wall 44 inFigure 7 determines the extent of swinging movement of the jaw It aboutthe pin 2!. This clearance should be as small as possible. However, itmust be sufiicient to permit complete disengagement of the teeth H andI3 and also permit such further separation as is necessary to preventengagement of the point of pawl I2 with the teeth H due to the limitedpossible cocking movement of the pawl during separation of the jaws. Thetooth depth determines the amount of movement required for separation,and the tooth spacing determines the amount of swinging movement of thejaw l6 which is nec essary to effect clamping of an object whose dimensions do not correspond to any possible adjustment of the pawl l2along the teeth I l. Consequently, if, as is preferred, the teeth aremade quite small, very little swinging movement of the jaw about pin [4is necessary to clamp tightly on any size object and, therefore, verylittle piv otal movement of the pawl 12 with reference to the sideplates I7 is required to insure distribution of the load over all of theteeth 13-. It is for that reason that the flat surfaces It of theopenings in the side plates H are designed to limit swinging movement ofthe pawl i2 with respect to the side plates.

It will be noted that the maintenance of par allelism of the jaws duringadjustments of the wrench results from the form and location of teeth i3with respect to the toggle linkage. So long as the paths of movement ofthe pins l4 and 2! are in substantially the same line or are insubstantially parallel lines, the faces of the laws will remainsubstantially parallel. In the preferred construction, the points of theteeth I l, instead of lying in a flat plane, lie in a plane which iscurved with a radius equal to the length of the toggle linkage made upof handle I and link 23; and the center of this radius is located at thepoint indicated by the numeral 49, which isthe same distance from theaxis of pin 25 as the distance separatin the axes of pins l4 and 2!. Theback wall of the opening 9' is also preferably curved about the samecenter and the points of the teeth [3 on the pawl I2 are located on asimilar convex curve so that they will properly mate with the teeth II.To further minimize deviations from parallelism, the face of jaw 16should extend at such an angle that 'it is" iii arallel to the faceofj-aw a when the toggle linkage is fully broken and the pointsof theteeth it on pawl I2 have advanced until they are in the same plane asthe points of the teeth ll. as the pawlteeth I3 complete their inwardmeshing movement, the jaw t5 willswing open slightly and the subsequenttoggle straightening operation will tend to return them to theclosedparall'el position.

The wrench mechanism described above will automatically release uponrelief of the handlesqueezing pressure, and the jaws will open to permitratcheting of the wrench about the nut for a gripi For some purposes,however, it desirable tohave a wrench which will act as a clamp and holditself in locked position upon object. Accordingly, Figures 9 and i0 isillustratedamodified form of the invention incorporating means for thatpurpose. The wrench illustrated fragment'arily in Figures 9* and 1 0 isidentical in constructionand mode of operation to the preferredembodiment previously de scribed except that the lever 50, whichcorresponds tothe lever 26 of the previous embodi ment, has anoseportion 5| which will permit the toggle linkage to swing slightly pastits dead center or straightened position when the heel of the lever isengaging the top surface of thelever 23. As a result, the wrench willmaintain itself in a clamped condition on any object until a 1 positiveseparating force is applied to the handles. I

A relatively thin sheet metal sleeve 52' surrounds and is slidable uponthe lever 23. When it is desired to use the tool in the usual manner asa wrench which will release automatically, the sleeve 52 is slid intothe position illustrated in Figure 9, in which it is interposed betweenthe heel of lever 50 and the top surface of lever 23. The thickness ofthe sleeve 52 is sufficient to prevent complete straightening of thetoggle linkage and, consequently, upon release of the handles, thewrench will automatically open. Sleeve 52 may be slid to the right, asviewed in Figure 9', to a position in which it does not contact thelever 50, in which event the tool is self-locking".

It will be observed that there is provided, in accordance with thepresent invention, an auto"! matically adjustable parallel jaw wrenchwhich, by a single squeezing movement of the handles, will close freelyon any size object and then apply a clamping force having exceedinglyhigh mechanical advantage, regardless of the size of the object clamped.The initial adjusting movement prior to engagement of the object is madewithout any mechanical advantage and, consequently, the forcemultiplying mechanism need only operate through the small final clampingmovement. The construction is such that the force multiplying mechanismmakes no appreciable movement until after the jaws have closed on theobject. As a result, an exceedingly high degree of force multiplicationmay be provided without limitin the overall range of adjustment.

While the wrench employs a ratchet holding mechanism, that mechanism isof such construction that an effective clamping action is achieved onobjects the size of which fall intermediate the increments of theratchet mechanism. Consequently, the wrench is, in effect, adjustable toany infinitesimal variation in the size of the workpiece. Moreover, bymaking. the ratchet teeth exceedingly small, the final clamping actionmay be effected without any appreciable departure of the jaws fromabsolute parallelism. In fact, due

to'th'eheavy clamping of the jaws on the object, aslight departure fromparallelism which may exist in certain cases will produce less anglebetween the faces of the jaws and the faces of a nut than will thenormal clearance provided in prior fixed wrenches.

Another important feature of the wrench resides in the fact that all ofthe heavy stresses to which the various elements of the wrench aresubject are directly applied tension or compression stresses, with theresult that distortion and fiexure, which would otherwise be encounteredifany'of the elements were subject to bending stresses, are avoided.Moreover, since the toggle mechanism pre-loads the wrench by clampingthe nut, no spreading or distortion of the wrench jaws will occur ontwisting a nut until the force at the nut corners due to the twistingaction exceeds the clamping force. The ratchet mechanism is peculiarlydesigned to provide maximum load capacity. Moreover,- the constructionis such that there is no danger of stripping the teeth of the ratchetmechanism; and, since during idle adjusting movements the ratchet teethare held out of engagement by spring 36 and lever 35, there is nopossibility of the points of theteeth being worn away or rounding 01f byrelative sliding engagement.

1 Another feature of the wrench resides in the fact that the adjustmentfor diiferent sizes of nuts is efiected by bodily swinging movements ofthe toggle linkage including the handle pl about the pivot 25 at therear end of handle 2. Consefluently, such adjustments do not have anyappreciable effect upon the spacing of the rear ends of the handles andit is thus possible to space the handles at the optimum distance for anormal hand grip.

It will be apparent that variations in the design and construction maybe indulged in without departing from the spirit of the invention. Thusthe size of the teeth II and i3 may be varied, depending upon the degreeof parallelism required in the wrench. Moreover, since the lengthof theopening 9 is relatively short compared to the length of the togglelinkage, the 'points of the teeth I I may lie in a flat plane parallelto the direction of movement of the movable jaw Without seriousdeparture from parallelism of the. jaws. The particular wrenchillustrated is so constructed that the jaws will not close into contactwith each other and hence is adapted for use on a range of nut sizes,from a maximum size which will fit the spacing of the jaws illustratedin Figure 1 to a minimum size which will fit the spacing illustrated inFigure 2. If so desired, the wrench may be so constructed by simplyaltering the shape of the jaws that the jaw faces contact each otherwhen the remaining parts are in the position shown in Figure 2. Such awrench would then operate on smaller range of sizes.

While the use of combined levers and springs for maintaining the togglebroken, the jaws open and the ratchet teeth out of contact provideoptimum performance, it will be apparent that the jaws may be maintainedbroken by a single leaf spring and the jaw movements controlled byeither one or two springs without using either of the levers 26 and 35.

Other variations in the design and construction will be obvious to thoseskilled in the art and may be indulged in without departing from thespirit of the invention or the scope of the appended claims.

What is claimed is:

'1..A wrench having a pair of handles adapted to be gripped in one hand,a jaw carried by one of said handles, an element mounted for slidingmovement with respect to said jaw in a direction approximately at rightangles to the face of said jaw, a second jaw pivoted on said element, apair of interconnected links forming a toggle linkage one of which linksis pivoted to the second jaw and the other to said one handle, resilientmeans connected to the toggle linkage and normally acting to break thetoggle linkage, the other handle being connected to the toggle linkagewith the result that a squeezing of said handles together tends to bringthe toggle linkage pivots into alignment and to swing said linkagebodily about its connection to the first handle in a direction to closethe jaws, the location of the points of connection of said togglelinkage 'to said second jaw and said one handle being such that thefaces of said jaws remain substantially parallel as said element slideswith respect to said one jaw, said one jaw having a plurality of teethfixed thereto and extending alongside the path of movement of saidelement, cooperating ratchet teeth on said element, a second resilientmeans connected to the second jaw and normally urging said teeth out ofengagement by limited pivotal movement of the second jaw about itsconnection to the toggle linkage, the teeth on said one jaw and the faceon the other jaw facing in the same direction around the axis of thepivotal connection between the toggle linkage and the other jaw, withthe result that engagement by the second jaw with an object locatedbetween the jaws when said handles are squeezed together will swing saidsecond jaw about its connection to the toggle linkage in a direction tocause engagement of said teeth and against the force exerted by thesecond resilient means, and the strength of said first resilient meansrelative to the strength of said second resilient means being such thatsqueezing of said handles together will cause engagement of said ratchetteeth before the toggle linkage begins to straighten.

2. A wrench having a fixed jaw, a movable jaw connected to the fixed jawfor pivotal and slidable movement with respect thereto, a toggle linkageconnecting the movable jaw to the fixed jaw and extending at approximateright angles to the direction of relative sliding movement between saidjaws, said toggle linkage including a handle member the majorhand-engaging portion of which is positioned between the points ofconnection of the linkage to the two jaws with the result that handpressure applied to the handle tends to slide the jaws toward eachother, means for holding said jaws against relative sliding movement inany one of a plurality of positions of adjustment to permit clamping ofan object by straightening of said toggle linkage and pivotal movementof the movable jaw, and resilient means for resisting straightening ofsaid toggle linkage in order to permit pressure exerted on said handleto slide the movable jaw toward the fixed jaw prior to engagement of anobject between said jaws without straightening of said to gle linka e.

, 3. A wrench having a pair of handles adapted to be gripped by onehand, a jaw fixed to one handle, a second jaw pivotally connected to theother handle, a link pivotally connected at one end to said one handleat a fixed point thereon and'at the other end to the second handleinter- 7 5 mediate its ends and forming with said other ascend ii'ii'diea toggieimkage; anew-neat connected to one handle for sliding movementin a, dime-- intersecting theplafie of the face of the first j swam in apath lying approximately on an arc of a circle having a radius equaltothel'ength of the straightened togglelinkage and having its centerpaced from said fixed point by a distance'e'qiial to' the distancebetween the pivotal connections between the second jaw and said otherhandle and said element, and a pivotal connection be"- twen the elementand'the' second jaw, said one handle and said element havingintereng'a'gin surfac s thereon ior'holding said element in" any one' ofa plurality" of positions with respect to said one handle.

4. A wrench having a pair of jaws, an element connected to one jaw forsliding movement relative to said jaw in a path approximately at rightangles to the plane of the jaw face; a pivotal connection between saidelement and the other jaw, a series of teeth on said one jaw which ex'-'tend alongside the path of movement of saidelement, said teeth pointingtoward said element, co-operatin'g' teeth on said element adapted tomesh with said first series of teeth, and a link mechanism pivotallyconnected to and between said jaws" and extending approximately at rightangles to the path of sliding movement of said element and co-operatingwith said element to guide said other jaw for movement toward and fromthe one jaw and maintain the" jaw faces substantially parallel, thepivotal connection be tween said link mechanism and said other jaw beingspaced from the pivotal connection between said element and said otherjaw, the teeth on said one jaw and the face on the' other jaw fz icingin the same direction around the axis of the" pivotal connection betweensaid other jaw and said link mechanism so' that a force appliedperpendicularly to the face of said other jaw will swing said other jawabout its pivotal connection to said link mechanism in a direction tocause" meshing of said teeth on the element with those on" said one jaw.

5. A wrench having a pair of jaws, an element connected to one jaw forsliding movement relative to said jaw in a path approximately at rightangles to the planes of the jaw face, a pivotal eonnection between saidelement and the other jaw, a series of teeth on said one jaw which ektendalongside the path of movement of said ele'-' ment, said teethpointing toward said element, o=operating teeth on said element adaptedto mesh with said first series of teeth, a link mecha pivotallyconnected to and between said jaws and extending approximately at rightangles to the path of sliding movement of said element and co-operatingwith said element to guide said other jaw for movement toward and fromthe one jaw and maintain the jaw faces substantially parallel, thepivotal connection between said link mechanism and said other jaw beingspaced from the pivotal connection be tween said element and said otherjaw, the teeth on said one jaw and the face on the other jaw facing inthe same direction around the axis of the pivotal connection betweensaid other jaw and said link mechanism so that a force appliedperpendicularly to the face of said other jaw will swing said other jawabout its pivotal connection to said link mechanism in a direction tocause meshing of saidteeth on the element with those on said one jaw,and a single resilient constantly urging" said otherjav'v in adii'e'c'tion to Separate Said jaws and also rotate 1 4 said? other jawabcut its" pivotal connection to said link mechanism in a direction tocause sep'' aration of said ratchet teeth so that engagement betweensaid teeth will not occur until a force isapplied tothe'face o'fsaidother jaw.

6. A wrench" having a pair of jaws, an element connected to-one jaw forsliding movement relativeto said jaw in a path approximately'at rightangles to the planes of the jaw face, a pivotal connection between saidelement and the other jaw', a' series of teeth on said one jaw which ex=tend alongside thepath'of movement of said ele-- ment, said teethpointing toward said element, co-op'e'r'ating teeth on said elementadapted to" mesh with said first series of teeth; a link mechapivo-tally connected to and between said jawsand extending approximatelyat right angles to the path of sliding movement of said element andcd-operating with said element to guide said other jaw for movementtoward and from the one" jaw and maintain the jaw faces substantiallyparallel, the teeth on said one jaw and the face on the other jaw facingin the same direc' tion around the axis of the pivotal connectionbetween said other jaw and said link mechanism so that a force appliedperpendicularly to the face of said other jaw will swing said other jawabout its pivotal connection to said link macha nism in a direction tocause meshing of said teeth on the element with those on said one jaw,and resilient means constantly urging said element out of contact withsaid teeth so that engag'ement between said teeth will not occur untilafter a; force is" applied to the face of said other jaw, said linkmechanism including means for pivoting said other jaw about its pivotalconnection to said element to apply a clamping force" to an objectbetween said jaws after said teeth have engaged.

'7. A wrei'ach having a pair of handles adapted to begripp'ed in onehand, a jaw carried by one" of said handles, an element mounted forsliding movement with respect to' said jaw in a direction approximatelyat right angles to the faceof said jaw, a second jaw pivoted on saidelement, a pair of interconnected links forming a toggle linkage one ofwhich links is pivoted to the second jaw and the other to said onehandle, resilient means norfnally acting tob'r'eak the toggle linkage toa limited degree s6 that: the linkage will swing as a unit about thepivctal connection to the handle, the other handle being associated withthe toggle linkage in such a manner that a squeezing of said handlestogether tends to bring the toggle linkage pivots into alignment and toswing said linkage bodily about its connection to the first handle in adirection to close the jaws, the location of the points of connection ofsaid toggle linkage to said secondjaw and said one handle being suchthat thefacs of said-jaws remain substantially parallel said elementslides with respect to said one jaw, said one jaw having a plurality ofteeth fixed thereto and extending alongside the path of movement of saidelement, co-operating teeth on said element, a second resilient meansnormally urging said teeth out of engagement by limited pivotal movementof the second jaw about its connection to the toggle linkage, the teethon said one jaw and the face on the other jaw facing in the samedirection around the axis of the pivotal connection between the togglelinkage and the other jaw, with the result that engagement by the secondjaw with an object located between the jaws when said handles aresqueezed together will swing said second jaw about its connection toange n the toggle linkage in a direction to cause engage! ment of saidteeth and against the force exerted by the second resilient means, andthe strength of said first resilient means relative to the strength ofsaid second resilient means being such that squeezing of said handlestogether will cause engagement of said teeth before the pivots of saidtoggle linkage are aligned.

8. A wrench having a pair of handles, a wrench jaw fixed on one handleat one extremity thereof with its jaw face extending approximatelyparallel to the length of the handle, a link pivotally connected at oneend of the other handle and at its opposite end to the oppositeextremity of said one handle and forming with said handle a togglelinkage, a member connected to said jaw for movement relative thereto ina direction approximately at right angles to the plane of the face ofsaid jaw, a second jaw pivotally connected at spaced points to saidother handle and said member whereby bodily pivotal movement of saidtoggle linkage about the axis of its connection to the first handle andtoward the first handle will cause said jaws toapproach each other,resilient means tending to separate said jaws, means to lock said memberagainst movement relative 'to said first jaw, and means to resistrelative pivotal movement between said handle and link in order toinduce said bodily pivotal movement of said toggle linkage when onehandle is forced toward the other.

9. A wrench having a fixed jaw, a movable jaw connected to the fixed jawfor pivotal and slidable movement with respect thereto, a toggle linkageconnecting the movable'jaw to the fixed jaw and extending at approximateright angles to the direction of relative sliding movement between saidjaws, said toggle linkage including a handle mem-' ber the majorhand-engaging portion of which is positioned between the points ofconnection of the linkage to the two jaws with the result that handpressure applied to the handle tends to slide the jaws toward eachother, means for holding said jaws against relative sliding movement inany one of a plurality of positions of adjustment to permit clamping ofan object by straightening of said toggle linkage and pivotal movementof the movable jaw, and resilient means for resisting straightening ofsaid toggle linkage in order to permit pressure exerted on said handleto slide the movable jaw toward the fixed jaw prior to engagement of anobject between said jaws without straightening of said toggle linkage,said last mentioned means including a lever pivoted on one of the linksand having a sliding engagement with the other link and acting as astrut to resist movement of the pivot point toward the other link, theline between the axis of the lever pivot and the point of contactbetween the lever and said other link lying at an acute angle tothecontacted link surface which decreases when the lever slides along saidother link incident to straightening of the toggle linkage, and a springacting between the lever and one of said links for exerting a forcetending to rotate said lever in a direction to increase said angle.

10. A wrench having a fixed jaw, a movable jaw connected to the fixedjaw for pivotal and slidable movement with respect thereto, a togglelinkage connecting the movable jaw to the fixed jaw and extending atapproximate right angles to the direction of relative sliding movementbetween said jaws, said toggle linkage including a handle member themajor hand-engaging portion of which is positioned between the points ofconnection of the linkage to the two jaws with the result that handpressure applied to the handle tends to slide the jaws toward eachother, means for holding said jaws against relative sliding movement inany one of a plurality of positions of adjustment to permit clamping ofan object by straightening of said toggle linkage and pivotal movementof the movable jaw, and resilient means for resisting straightening ofsaid toggle linkage in Orderto permit pressure exerted on said handle toslide the movable jaw to-' ward the fixed jaw prior to engagement of anobject between said jaws without straightening of said toggle linkage,said last mentioned means including a lever pivoted on one of the linksand having a sliding engagement with the other link and acting as astrut to resist movement of the pivot point toward the other link, theline between the axis of the lever pivot and the point of contactbetween the lever and said other link ly ing at an acute angle to thecontacted link surface whi-ch decreases when the lever slidesalong saidother link incident to straightening of the toggle linkage, and a springacting between the lever and one of said links for exerting a forcetending to rotate said lever in a direction to increase said angle, theangle between the line of force exerted by the spring on the lever andsaid line between the lever pivot and point of contact being such thatthe effective lever arm of the spring force on the lever reduces as thetoggle linkage is straightened, said lever having a portion which actsas a positive abutment between said handle and other link to preventsaid toggle linkage from breaking in one direction.

11. A wrench having a pair of generally parallel handles adapted to begripped by one hand, a jaw fixed on the forward end of one handle, asecond jaw mounted for sliding movement relative to the first jaw in'adirection approximately at right angles to said handles, a pivotalconnection between the forward end of the other handle and the secondjaw with the result that when the forward ends of said handles aresqueezed toward each other the jaws are caused to approach and when therearward ends of the handles are moved toward each other the otherhandle pivots around its connection to the second jaw, automatic meansoperable in response to engagement of said jaws on an object for holdingsaid jaws against relative sliding movement, yielding means connected tothe other handle for resisting movement of the rear ends of the handlestoward each other, separate yielding means connected to the jaws forseparating the jaws, and force multiplying means connected to said otherhandle and operable when the rear ends of said handles are moved towardeach other to force, said jaws toward each other while the reactionforce is sustained by said automatic means.

12. A wrench having a fixed jaw, a movable jaw connected thereto, a pairof handles connected to said jaws for moving the jaws toward each other,a lever pivoted to one jaw and engaging the other, and a springconnected to the lever and to said one jaw and exerting a force tendingto swing said lever in a direction to separate said jaws, the anglebetween the line of the force exerted by the spring on the lever and aline through the point of connection between the spring and lever andthe pivotal axis of the lever being an acute angle which increases asthe lever. swings in a direction to separate the jaws with 1 7 theresult that the effective lever arm of the spring force on the leverreduces in approximate proportion to the increase in the force appliedby the spring to the lever as the jaws move toward each other.

' JOHN A. BLAIR.

REFERENCES CITED The following references are of record in the file ofthis patent:

Number 1,445,280

